1. Field of the Invention
The present invention relates to an adhesive pit and fissure sealant useful in dental practice. More particularly, the present invention relates to an adhesive pit and fissure sealant which is useful in the sealing of pits and fissures of sound teeth to prevent teeth from decaying, and to a method for sealing the same.
2. Description of the Prior Art
The occlusal surfaces of molars have pits and fissures. Food debris and the like penetrate the pits and fissures which eventually results in dental caries. Recently, attempts have been made to seal pits and fissures for the purpose of preventing dental caries.
In an attempt to achieve this purpose Takeuchi et al developed a process to protect sound teeth by coating the teeth with a lower alkyl .alpha.-cyanoacrylate over the openings of the pits and fissures. The powder containing PMMA as a base is added thereto and pressed into the pits and fissures which protects the sound teeth (Japanese Pat. No. 689,555). M. G. Buonocore et al have developed a process which comprises etching the surface of teeth with acid and then covering the etched surface with a mixture previously formed from methyl cyanoacrylate and PMMA powder (Journal of the American Dental Association 75, 121, 1967). M. G. Buonocore also developed a sealant consisting of as major ingredients, three parts by weight of the reaction product of bisphenol A and glycidyl methacrylate and one part by weight of methyl methacrylate monomer in which approximately 2% benzoin methyl ester is dissolved as an ultraviolet light sensitive catalyst (Journal of the American Dental Association, 80, 324, 1970). Further, Takeuchi et al have found a tooth filling material useful for sealing cracks, fissures and cavities consisting of a monomeric lower alkyl .alpha.-cyanoacrylate, such as ethyl .alpha.-cyanoacrylate monomer. The monomer is applied to the tooth followed by a second material comprising microfine particles of a dentally acceptable solid material having a particle size of about 3 to 500 microns, which particles may be in admixture coated with lower alkyl methacrylate polymer, such as methacrylate polymer powder. The dentally acceptable solid materials include gold, silver, nickel, tin, aluminum, platinum, indium, copper, iron, chromium, stainless steel, brass, indium-silver alloy, porcelain and fibrous or powdery glass (U.S. Pat. No. 3,518,762).
As reported by the Committee of the American Dental Association and the Scientific Group of WHO, tooth sealants require simple procedures and short practice times as well as long supporting times. Viewed in this light, the sealing procedure which employs sealants made by Buonocore is complicated and requires long hardening times, i.e., more than 30 seconds, Also, the sealants disclosed in Takeuchi's U.S. patent have the disadvantage that adhesion is decreased even when applied to teeth etched with acid.
A need, therefore, continues to exist for a method of treating dental pits and fissures with a sealing composition by simple procedures and in short practice times.